Free plate motor or pump



y 16, 1967 E. ORSHANSKY, JR 3,319,576

FREE PLATE MOTOR OR PUMP 4 Sheets-Sheet 1 Filed Sept. 24, 1965 ATTORNEYS 16, 1967 E. ORSHANSKY, JR 3,319,576

FREE PLATE MOTOR 0R PUMP 4 Sheets-Sheet 2 Filed Sept. 24, 1965 INVENTOR. ELIAS ORSHANSKY,JR.

ATTORNEYS May 16, 1967 Filed Sept. 24, 1965 FREE PLATE MOTOR OR PUMP 4 Sheets-Sheet 3 INVENTOR.

ELIAS ORSHANSKY JR.

ATTORNEYS y 6, 1967 E. ORSHANSKY, JR 3,319,576

FREE PLATE MOTOR OR PUMP Filed Sept. 24, 1965 4 Sheets-Sheet 4 ROTATION INVENTOR. EILAS ORSHANSKY ,JR.

ATTORN EYS United States Patent Ofiiice 3,3l9,575 Patented May 16, 1967 3,319,576 FREE PLATE MOTOR R PUMP Elias Orshansky, Jr., 1679 Lombard St., San Francisco, Calif. 94109 Filed Sept. 24, 1965, Ser. No. 489,822 Claims. (Cl. 103-173) This invention relates to a hydraulic motor or pump and more specifically relates to a variable displacement hydraulic motor.

An object of the present invention is to provide a hydraulic motor or pump of generally improved design, which is capable of transmitting a large amount of power for its size, which has relatively few and simple parts and which is capable of going from minimum to maximum displacement with high efliciency.

Another object of the present invention is to provide a motor or pump having free wobble plates which enables one to employ a simple yet highly effective tilting mechanism for the wobble plates.

Another object of the invention is to provide a novel stepped piston arrangement whereby a large bearing area can be employed in comparison with the elfective area of the piston, minimizing wear.

A further object of this invention is to provide a novel valving arrangement employing a combination of paired and spool valves wherein one valve of each pair has two lands and the other has three lands.

A still further object of the invention is to provide a structure wherein all of the forces are substantially balanced.

Other objects will be apparent from the balance of the specification which follows.

In the drawings forming part of this application:

FIGURE 1 is a side view in section of a motor embodying this invention, said view being taken on a skewed plane, the left-hand side of the drawing being on the plane 2A2A of FIGURE 2, the next section on the plane 3A3A of FIGURE 3, and the right-hand section of the drawing on the line 4A-4A of FIGURE 4.

FIGURE 2 is a section of the line 22 of FIGURE 1.

FIGURE 3 is a section on the line 3-3 of FIGURE 1.

FIGURE 4 is a section on the line 4-4 of FIGURE 1 but with the eccentrics displaced substantially 90.

FIGURE 5 is a diagrammatic view to explain the valving arrangement employed.

Referring to the drawings by reference characters, there is shown a motor having a fixed housing generally designated 7, within which is mounted a rotor assembly, generally designated 9, the rotor being mounted for rotation within the housing by means The rotor includes a shaft one end thereof to which may be attached a suitable power take-off or driving assembly, not shown. Mounted on the shaft and rotatable therewith is an elongated collar 19 having tongues 21 at each end thereof, the tongues having racks 23 thereon. Further, collar 19 has an end member 25 to which a suitable control can be attached, not illustrated, to move the collar back and forth and thus vary the displacement, as is hereinafter described in detail. Each end of the shaft 15 has splines 27 carrying pad support members 29. Pad support members 29 have an upper bearing 31 and a lower bearing 33 through which the shafts 35 and 37 pass. Shafts 35 and 37 have teeth 39 and 41 which mesh with the rack teeth 23. The shafts 35 and 37 have eccentric ends 43 with counterweights 44 aflixed to the ends. Four power take-off pads 45 are provided at each end of the machine, each of the pads having a flat face 51 and a boss 53 suitably jouraaled for reception of the eccentric end portion 43 of shaft 35. As the collar 19 is traversed, the racks act on :he shafts turning the shafts and thus moving the ec- 15 having splines 17 at of the bearings 11 and 13. v

centrics. Since the eccentricsare 180 out of phase on the upper and lower shafts, an upper pair of pads is pushed in one direction while the lower pair of pads is moved in the opposite direction. The pad support members 29 also support cam tracks 55 and 57 at each end of the motor. These cam tracks are used for actuating the valves as is hereinafter explained. The inner surfaces 58 of cams 57 form a cylinder which is used to loosely hold and locate the wobble plates, hereinafter described.

Mounted Within the housing 7 and affixed thereto is the cylinder block 59 which provides cylinders both for the driving pistons and also the spool valves as well as providing passages for the introduction of and withdrawal of the hydraulic fluid which is used to actuate the motor or pump. Located within the cylinder block 59 are the power pistons as at 61 and 63. In the embodiments of the invention illustrated, there are ten such pistons with fixe extending from each end of the block, i.e. against each of the wobble plates. The cylinder block also provides cylinders for the spool valves which may have either three lands, as the valve at 65, or the two land spool valve as at 67. There are five of the two spool valves and five of the three spool valves, the three and two spool valves alternating around the periphery of the block. Passages are provided within the block for the introduction of high pressure oil to the valves and thus the pistons. Passage 69 is for the high pressure hydraulic fluid while passage 71 constitutes the outlet for the low pressure fluid or vice versa, depending upon the direction of rotation. These passages extend completely around the periphery of the housing and are provided with outlet and inlet connections as at 72.

All of the power pistons are identical so that only one will be described. Thus piston 61 has a shank portion '73 with a hollow interior 75 into which the retracting rod 77 telescopes in sealing relationship. Piston 61 has a large hemispherical opening at one end thereof into which a ball 79 is free to rotate, the ball 79 having a flat face 81 which is adapted to be pressed against a wobble plate 83 by a similar but smaller ball 85 at the opposite end of the retracting rod 77. Ball 35 is in contact with the opposite wobble plate 87. Each of the wobble plates is free to rest between the pistons and the power take-off pads and has a spherical periphery 89 so that the wobble plate is free to ride in the cylinder 58. Normally, the wobble plates will rest against and turn with the pads since the balls at the ends of the pistons are provided with a hollow face 91 into which oil is passed through the passages 93 and 95, so that the friction is greatest between the wobble plate and the pad. The smaller balls used at the opposite end of the rod have similar passages. A spring 97 biases the piston 61 and rod 77 outwardly, keeping the ends of the pistons in contact with the wobble plates at the opposite ends of the motor. It will be seen that the effective area to which pressure is applied to the piston 61 is diminished by the area of the rod 77 so that its efiFective area is much less than its overall diameter, permitting the ball 79 to be rather large yet tucked into the piston, thereby minimizing wear and side thrust both on the ball and the piston against the cylinder in which it reciprocates. Further, it will be noted that rod 77 forms a tight fit with the cylinder block only near the edge of the block, increasing the tolerance for eccentricity between the large and small cylinders. A passage 99 communicates with the space behind the piston 61 and its mating three land spool valve 65. Similarly, a passage 101 communicates with the space behind the piston 103 and its mating two land spool valve 67. In the embodiment illustrated, the five pistons operating against the wobble plate 83 are controlled by three land valves, while those operating against the wobble plate 87 are controlled by the two land valves.

It will be seen that the pads define a larger circle than the pressure points of the pistons against the wobble plates, so that the plates are always fully supported and there is no tendency for the plates to rise off the pads.

Each of the three land spool valves, as valve 65, has end lands 105 and 107 and a center land 109. The valves have hollow ends with inserts 111 and 113 at either end thereof, each of which terminates in hemispherical bearings 115 and 117 riding on the cam tracks 57. At one end, a spring 119 urges the members outwardly, while the opposite insert rides against a shoulder 121 so that the valve body is definitely located with respect to one of the cam tracks, yet is kept in contact with both of the cam tracks by the spring. The two land valves as at 67 are similar except that they have no center land.

-It will be noted that in the retractors for both the pistons and valves there is sufficient travel so that the parts will not bottom if one should get stuck in the cylinder bore.

The action of the valves can best be seen from the schematic diagram of FIGURE wherein the solid lines represent the drive cams, while the dash-dot line represents a valve cam. In the schematic diagram, different numbers are used from those used above to avoid confusion and the description is of the device when it operates as a motor. Thus, in the diagram there is a low pressure line 123 and a high pressure line 125. These lines run completely around a periphery of the motor. To take specific instances on the diagram, the three land valves 127 is moving upwardly, and it will be seen that the space behind the piston 129 is placed in fluid communication with the high pressure line 125. As rotation continues, the direction of the three land valve reverses as at 131, although the piston 133 is still moving downwardly. This action continues as at 135, but as the valve gets to the position shown at 137, the center land has cut off the high pressure line and has placed the space behind piston 139 in fluid communication with the low pressure line 123. At this point the direction of movement of the piston has also reversed. At 141 the three land valve has moved upwardly so that the center land is about to cut oif the low pressure line and restore the high pressure line as was shown in 127 and 129.

Referring now to the action of the two land valves operating the opposite set of pistons, it will be seen, for instance, that the piston 143 is at the middle of its stroke while its mating two spool valve 145 is reversing direction. On the other hand, valve 147 is at the center of its stroke, while its mating piston 149 is reversing direction.

In the embodiment illustrated, the shafts 35 and 37 are not on a plane at right angles to shaft 15 but are offset from a plane in opposite directions. This is the optimum situation for a motor or for a pump wherein the same line is always the high pressure line. In the case of a pump wherein it is desired that the high and low pressure lines be reversed undersome operating conditions, it is neces sary that the wobble plates go over center, in which case shafts 35 and 37 would be on the same plane.

I claim:

1. A variable displacement hydraulic motor or pump comprising in combination:

(a) a fixed cylinder block,

(b) a shaft mounted for rotation therein,

(c) a collar on said shaft and rotatable therewith, said collar being mounted for reciprocation on said shaft,

(d) wobble plates at each end of said shaft lying adjacent said cylinder block,

(e) pads supports members at each end of said aflixed thereto, (f) power take members, said wobble plates,

(.g) rack means on said collar and mating pinion means on said pad supports whereby the position of said collar determines the angle which the pads make with the shaft, 7

(h) a first set of pistons mounted for reciprocation in said block, each of said pistons having a head pressing against one of said wobble plates and a retractor pressing against the opposite wobble plate,

(i) a second set of pistons alternating with said first set of pistons, each of said second set of pistons having heads and retractors mounted in the opposite direction from said first set of pistons,

(j) said wobble plates freely floating between said pistons and said pads, and

(k) valve means associated with said pistons controlling the How of hydraulic fluid thereto.

2. The structure of claim 1 wherein the retractor telescopes in sealing relationship with the piston whereby the effective pressure area of the piston is substantially less than the actual area of the cylinder in which the piston reciprocates.

3. The structure of claim 2 wherein each piston has a head mounted on a hemispherical balland wherein the area of the ball is relatively large in comparison with the efiective presure area of the piston.

4. The structure of claim 1 wherein the valves for-the pistons acting against one wobble plate comprise two land spool valves and the valves for the pistons operating against the opposite wobble plate comprise three land spool valves.

5. The structure of claim 1 wherein the pads supporting the wobble plates define a larger circle than the pressure circle of the pistons acting against the wobble plates.

shaft 011 pads mounted on said support pads defining the position of the References Cited by the Examiner UNITED STATES PATENTS 1,418,951 6/ 1922 Martin -103162 2,431,686 12/ 1947 Deschamps 103-173 FOREIGN PATENTS 791,604 3/ 8 Great Britain.

DONLEY J. STOCKING, Primary Examiner,

W. L. FREEH, Assistant Examiner, 

1. A VARIABLE DISPLACEMENT HYDRAULIC MOTOR OR PUMP COMPRISING IN COMBINATION: (A) A FIXED CYLINDER BLOCK, (B) A SHAFT MOUNTED FOR ROTATION THEREIN, (C) A COLLAR ON SAID SHAFT AND ROTATABLE THEREWITH, SAID COLLAR BEING MOUNTED FOR RECIPROCATION ON SAID SHAFT, (D) WOBBLE PLATES AT EACH END OF SAID SHAFT LYING ADJACENT SAID CYLINDER BLOCK, (E) PADS SUPPORTS MEMBERS AT EACH END OF SAID SHAFT AFFIXED THERETO, (F) POWER TAKE OFF PADS MOUNTED ON SAID SUPPORT MEMBERS, SAID PADS DEFINING THE POSITION OF THE WOBBLE PLATES, (G) RACK MEANS ON SAID COLLAR AND MATING PINION MEANS ON SAID PAD SUPPORTS WHEREBY THE POSITION OF SAID COLLAR DETERMINES THE ANGLE WHICH THE PADS MAKE WITH THE SHAFT, (H) A FIRST SET OF PISTONS MOUNTED FOR RECIPROCATION IN SAID BLOCK, EACH OF SAID PISTONS HAVING A HEAD PRESSING AGAINST ONE OF SAID WOBBLE PLATES AND A RETRACTOR PRESSING AGAINST THE OPPOSITE WOBBLE PLATE, 